The Myth of the Reliability Test

The U.S. Supreme Court’s ruling in Daubert v. Merrell Dow Pharmaceuticals, Inc., and subsequent revisions to Federal Rule of Evidence 702, was supposed to usher a reliability revolution. This modern test for admissibility of expert evidence is sometimes described as a reliability test. Critics, however, have pointed out that judges continue to routinely admit unreliable evidence, particularly in criminal cases, including flawed forensic techniques that have contributed to convictions of innocent people later exonerated by DNA testing. This Article examines whether Rule 702 is in fact functioning as a reliability test, focusing on forensic evidence used in criminal cases and detailing the use of that test in states that have adopted the language of the 2000 revisions to Rule 702. Surveying hundreds of state court cases, we find that courts have largely neglected the critical language concerning reliability in the Rule. Rule 702 states that an expert may testify if that testimony is “the product of reliable principles and methods,” which are “reliably applied” to the facts of a case. Or as the Advisory Committee puts it simply, judges are charged to “exclude unreliable expert testimony.” Judges have not done so in state or federal courts, and in this study, we detail how that has occurred, focusing on criminal cases

Flow induced ultrasound scattering: experimental studies

Sound scattering by a finite width beam on a single rigid body rotation vortex flow is detected by a linear array of transducers (both smaller than a flow cell), and analyzed using a revised scattering theory. Both the phase and amplitude of the scattered signal are obtained on 64 elements of the detector array and used for the analysis of velocity and vorticity fields. Due to averaging on many pulses the signal-to-noise ratio of the phases difference in the scattered sound signal can be amplified drastically, and the resolution of the method in the detection of circulation, vortex radius, vorticity, and vortex location becomes comparable with that obtained earlier by time-reversal mirror (TRM) method (P. Roux, J. de Rosny, M. Tanter, and M. Fink, {\sl Phys. Rev. Lett.} {\bf 79}, 3170 (1997)). The revised scattering theory includes two crucial steps, which allow overcoming limitations of the existing theories. First, the Huygens construction of a far field scattering signal is carried out from a signal obtained at any intermediate plane. Second, a beam function that describes a finite width beam is introduced, which allows using a theory developed for an infinite width beam for the relation between a scattering amplitude and the vorticity structure function. Structure functions of the velocity and vorticity fields deduced from the sound scattering signal are compared with those obtained from simultaneous particle image velocimetry (PIV) measurements. Good quantitative agreement is found.Comment: 14 pages, 23 figures. accepted for publication in Phys. Fluids(June issue

Genetic Map of Bacteriophage [var phi]X174

Bacteriophage [var phi]X174 temperature-sensitive and nonsense mutations in eight cistrons were mapped by using two-, three-, and four-factor genetic crosses. The genetic map is circular with a total length of 24 × 10−4wt recombinants per progeny phage. The cistron order is D-E-F-G-H-A-B-C. High negative interference is seen, consistent with a small closed circular deoxyribonucleic acid molecule as a genome

A Broad Search for Counterrotating Gas and Stars: Evidence for Mergers and Accretion

We measure the frequency of bulk gas-stellar counterrotation in a sample of 67 galaxies drawn from the Nearby Field Galaxy Survey, a broadly representative survey of the local galaxy population down to M_B-15. We detect 4 counterrotators among 17 E/S0's with extended gas emission (24% +8 -6). In contrast, we find no clear examples of bulk counterrotation among 38 Sa-Sbc spirals, although one Sa does show peculiar gas kinematics. This result implies that, at 95% confidence, no more than 8% of Sa-Sbc spirals are bulk counterrotators. Among types Sc and later, we identify only one possible counterrotator, a Magellanic irregular. We use these results together with the physical properties of the counterrotators to constrain possible origins for this phenomenon.Comment: 19 pages, 4 figures, AJ, accepte

An Editor in Israel: The Periodicals of Ahad Ha'am in the Development of Modern Hebrew Literature

This dissertation argues for a reevaluation of the significance of Ahad Ha’am (Asher Ginsberg) in the development of modern Hebrew literature on the basis of his work as an editor of periodicals. Critics commonly portray Ahad Ha’am as rigid and didactic, enforcing his own literary norms while excluding aesthetic and humanistic literature in favor of literature with explicit Jewish themes. Reading the periodicals edited by Ahad Ha’am shows that this reputation is exaggerated; his work is in fact characterized by significant heterogeneity and flexibility.This dissertation introduces the critical perspective and methodology of periodical studies to Hebrew literature. The first chapter shows how Ahad Ha’am as an editor brings diverse ideologies and Hebrew styles together in an organic whole, the “Odessa nusach,” in the literary collection Kaveret (1890). The second chapter argues that Yehoshua Ḥana Ravnitsky, editor of Pardes (1892-1896), lacks the editorial skill and vision of Ahad Ha’am, and as a result Pardes is divisive and lacks the unity of Ahad Ha’am’s periodicals. The final two chapters are devoted to Ha-Shiloah, the most prestigious outlet for Hebrew literature of its era, founded and edited by Ahad Ha’am from 1896 to 1903. Chapter Three traces the history of the critical reception of Ahad Ha’am’s controversy with Micha Yosef Berdichevsky over the boundaries of Hebrew literature, showing the development of a polarized standard account of the dispute that discredits Ahad Ha’am. Reading the original essays of the dispute in context shows that Ahad Ha’am’s resistance to belles lettres and humanistic literature is far from absolute, and in a sense Ahad Ha’am authors the entire controversy by collaborating with and publishing Berdichevsky and his supporters. Finally, the dissertation uses the belletristic literature published by Ahad Ha’am in Ha-Shiloah to show that his selections as an editor were not as narrow as critics claim or even as Ahad Ha’am himself prescribes in his essays. As a periodical editor, Ahad Ha’am fostered diversity and dialogue, and this should be accounted for in evaluating his influence on the development of Hebrew literature

Physical Sources of Scatter in the Tully-Fisher Relation

We analyze residuals from the Tully-Fisher relation for the emission-line galaxies in the Nearby Field Galaxy Survey, a broadly representative survey designed to fairly sample the variety of galaxy morphologies and environments in the local universe. For spirals brighter than M_R^i=-18, we find strong correlations between Tully-Fisher residuals and both B-R color and EW(Halpha). The extremes of the correlations are populated by Sa galaxies, which show consistently red colors, and spirals with morphological peculiarities, which are often blue. If we apply an EW(Halpha)-dependent or B-R color-dependent correction term to the Tully-Fisher relation, the scatter in the relation no longer increases from R to B to U but instead drops to a nearly constant level close to the scatter we expect from measurement errors. We argue that these results probably reflect correlated offsets in luminosity and color as a function of star formation history. Broadening the sample in morphology and luminosity, we find that most non-spirals brighter than M_R^i=-18 follow the same correlations as do spirals, albeit with greater scatter. However, the color and EW(Halpha) correlations do not apply to galaxies fainter than M_R^i=-18 or to emission-line S0 galaxies with anomalous gas kinematics. For the dwarf galaxy population, the parameters controlling Tully-Fisher residuals are instead related to the degree of recent disturbance: overluminous dwarfs have higher rotation curve asymmetries, brighter U-band effective surface brightnesses, and shorter gas consumption timescales than their underluminous counterparts. As a result, sample selection strongly affects the measured faint-end slope of the Tully-Fisher relation. Passively evolving, rotationally supported galaxies display a break toward steeper slope at low luminosities.Comment: 58 pages including 21 figures, AJ, accepte

The Cryogenic Refractive Indices of S-FTM16, a Unique Optical Glass for Near-Infrared Instruments

The Ohara glass S-FTM16 is of considerable interest for near-infrared optical designs because it transmits well through the K band and because negative S-FTM16 elements can be used to accurately achromatize positive calcium fluoride elements in refractive collimators and cameras. Glass manufacturers have sophisticated equipment to measure the refractive index at room temperature, but cannot typically measure the refractive index at cryogenic temperatures. Near-infrared optics, however, are operated at cryogenic temperatures to reduce thermal background. Thus we need to know the temperature dependence of S-FTM16's refractive index. We report here our measurements of the thermal dependence of S-FTM16's refractive index between room temperature and ~77 K. Within our measurement errors we find no evidence for a wavelength dependence or a nonlinear temperature term so our series of measurements can be reduced to a single number. We find that Delta n_{abs} / Delta T = -2.4x10^{-6} K^{-1} between 298 K and ~77 K and in the wavelength range 0.6 micron to 2.6 micron. We estimate that the systematic error (which dominates the measurement error) in our measurement is 10%, sufficiently low for most purposes. We also find the integrated linear thermal expansion of S-FTM16 between 298 K and 77 K is -0.00167 m m^{-1}.Comment: 8 pages, including 9 figures. Uses emulateapj.cls. Accepted for publication in PAS

Ground-layer wavefront reconstruction from multiple natural guide stars

Observational tests of ground layer wavefront recovery have been made in open loop using a constellation of four natural guide stars at the 1.55 m Kuiper telescope in Arizona. Such tests explore the effectiveness of wide-field seeing improvement by correction of low-lying atmospheric turbulence with ground-layer adaptive optics (GLAO). The wavefronts from the four stars were measured simultaneously on a Shack-Hartmann wavefront sensor (WFS). The WFS placed a 5 x 5 array of square subapertures across the pupil of the telescope, allowing for wavefront reconstruction up to the fifth radial Zernike order. We find that the wavefront aberration in each star can be roughly halved by subtracting the average of the wavefronts from the other three stars. Wavefront correction on this basis leads to a reduction in width of the seeing-limited stellar image by up to a factor of 3, with image sharpening effective from the visible to near infrared wavelengths over a field of at least 2 arc minutes. We conclude that GLAO correction will be a valuable tool that can increase resolution and spectrographic throughput across a broad range of seeing-limited observations.Comment: 25 pages, 8 figures, to be published in Astrophys.

An analysis of spectra in the Red Rectangle nebula

This paper presents an analysis of a series of spectra in the Red Rectangle nebula. Only the reddest part of the spectra can safely be attributed to light from the nebula, and indicates Rayleigh scattering by the gas, in conformity with the large angles of scattering involved and the proximity of the star. In the blue, light from HD44179, refracted or scattered in the atmosphere, dominates the spectra. This paper questions the reliability of ground-based observations of extended objects in the blue.Comment: 25 figure